When Isla Fisher first met Kirsten Dunst, the encounter could have been scripted from one of the madcap comedies that put these two popular Hollywood actresses on the map. The setting: backstage at the Oscars. The setup: Dunst was attending the awards ceremony accompanied by her brother, Christian; Fisher was there with her then-fiancé, actor Sacha Baron Cohen, who was nominated for his film, Borat.

Dunst mistook Cohen–in black tie and without his thick mustache–for a waiter and sent him to fetch her Champagne, which in good fun, the comic attempted to retrieve. Fisher laughs at the memory. "He thought you knew who he was and were making a joke. He thought you had a great sense of humor!"

No harm done–Fisher and Dunst, who worked together in the 2012 comedy Bachelorette, have an easy rapport, which was on display during a recent chat about Fisher's latest role in the highly anticipated Baz Luhrmann film, The Great Gatsby, based on F. Scott Fitzgerald's classic novel about love, class tensions, and ambition in Roaring Twenties New York. The movie, set to be released May 10 and the opening film of the Cannes Film Festival, also stars Leonardo DiCaprio, Carey Mulligan, and Tobey Maguire. In the film, Fisher plays the doomed Myrtle Wilson. Stuck in an unhappy marriage and living on the wrong side of the tracks, Wilson carries on an affair with the wealthy Tom Buchanan (played by Joel Edgerton) with disastrous consequences.

KIRSTEN DUNST: Tell us about Myrtle Wilson, your character in The Great Gatsby.
ISLA FISHER: I wanted to portray Myrtle as a woman who is really in love. She thinks she married beneath herself and is stuck in a loveless marriage. Tom is authoritative and controlling–the opposite of [her husband] George—and she thinks his violence is a sign of masculinity. At the beginning, she may have been attracted to Tom for his wealth. I added the emotionally insecure side, but I also gave her a grounded, loving “Tom is my hero and he will rescue me from my status” vibe.

KD: Makes total sense; it’s not about the money at all.
IF: You feel sorry for Myrtle because she really doesn’t have the breeding or the class, and yet she’s in these aristocratic circles. She’s such a try-er. I really love Myrtle. I know when you talk to people about the book, they have conflicted feelings about her, but because I played her, it’s hard for me not to connect with her and feel her pain.

KD: Many of the themes of The Great Gatsby—the widening discrepancies in wealth and the dangers of self-invention—are still highly topical. What do you think audiences will take away from the film?
IF: I haven’t seen the film yet, so it’s hard for me to [say exactly, but] the characters are elitist, reinforce social boundaries, and put [an emphasis] on money and materialism. They lack compassion for one another. I think those messages will hit home because all those issues are so relevant today.

KD: Much of Gatsby was shot in Australia, where you grew up. How did it feel working on such a large-scale production at home?
IF: It was thrilling and terrifying. Given the caliber of the director and cast on Gatsby, I definitely felt out of my comfort zone. I did feel like I was going to be called out and sent home at some point—you always feel very insecure, at least I do. But I got to eat Vegemite toast for breakfast and swim on Bondi Beach.

KD: How was working with Baz Luhrmann?
IF: He’s clever, creative, and collaborative; and the set was like a playground of rich costumes (his wife Catherine Martin does them) and color and music and laughter. You do a lot of takes and a lot of improvisation. The camera is always moving; you don’t know [when] he’s going to come to you. During the party scenes, I’d be dancing, and there’s a camera in my face when I thought it was Tobey [Maguire]’s close-up. I love that. I will say this about Baz—he’s a perfectionist, so you relax because you know he’s thought of everything. Everybody cares on a Baz Luhrmann film set because everyone is so effing grateful to be there.

KD: Did you keep any souvenirs from this set or anything from the movies you have done?
IF: I just keep my notes on my scripts, and the music I use for a character. I always have to have songs for a character. Baz gave lots of music, which was wonderful, and lots of images, which I really appreciated.

KD: Do you ever worry about being labeled a comedic actress and not being considered for serious dramatic parts?
IF: I don’t want to consider someone’s interpretation about me—it freaks me out. I have to be me and disassociate that way. I think no one should be labeled. I go up for gigs, and if it’s the right character for me and it’s shot in [the right location].... a lot of me agreeing to do work is about logistics because of my kids.

KD: Many times comedians surprise with a dramatic turn.
IF: I wouldn’t describe myself as a comedienne. I’m a comic actress; I don’t really do standup or write my own material. I write my own improv within a movie, but I would say I enjoy working on a comedy more. I don’t really act with the goal of accolades in mind, I’m pretty happy in my genre. I just try to do my own thing. Life’s about the journey; you don’t want to think about the destination.

KD: Who do you look up to or want to emulate?
IF: Goldie Hawn [in] some of those movies in the ’80s.... Overboard is the best physical comedy I’ve seen. She’s a huge influence.

KD: How has becoming a wife and a mother changed the way you work?
IF: Even when you don’t take your kids with you, your mind and heart are busy with them. It would be very hard for me to play scenes where a mother lost a child—I wouldn’t want to play that scene in Jude, where Kate Winslet finds her babies murdered. I’m just not ready to put my head into that kind of stuff while mine are so small. That’s why I’m drawn to lighter material.

KD: You took a break in the beginning of your career to have kids.
IF: I did; I took three years off. It’s not like you’re taking a break and looking on IMDbPro to see your StarMeter falling. You’re doing the most important, incredible thing. When you come back in, the perspective has changed. I truly believe you can’t have it all and you shouldn’t want to. In [the kids’ book] Pinkalicious the mum goes, “You get what you get and you don’t get upset.” It’s written for toddlers, but I just love that expression. It’s kind of my catchphrase when it comes to the business.

KD: You just went to Brazil for Save the Children. Why did you become involved with this group?
IF: I heard that 830,000 babies lives would be saved every year if they were breast-fed. Save the Children and I feel that countries need to increase their breast-feeding rates. This is such a natural way to stop babies from dying. We’re targeting the developing world, where women don’t have access to clean water to mix with formula or to sterilize bottles. There’s this new report called “Superfood for Babies” about breast-feeding, and the stats are just scary. I felt that no matter where mummy lives, she needs access to the support and the information to help her breast-feed if she wants to.

KD: Where do you like to hang out in NYC?
IF: I love to go to Central Park, obviously, and I love it in winter when it’s covered in snow—it’s so magical. And I like to do tea at The Plaza with my girls. I love Battery Park City. I have the greatest time there; it is always quiet. [There is] such a beautiful view looking over at the Statue of Liberty. I like going on my bike along that little bikeway on the West Side Highway. I love nothing better than the inhalation of some fumes along the West Side Highway! [Laughs]

KD: You look like you’re 12. Is this because you’re a redhead and stay out of the sun? What’s the secret?
IF: My theory is the minute you stop partying, your skin rejuvenates. I haven’t partied in years. Not that I ever really partied. I’m definitely not that girl who’s exfoliating, moisturizing, plucking, waxing. I’m low maintenance.

KD: Are you and Sacha going to work together?
IF: Personally, I think we collaborate on enough behind closed doors. We’re working on some really important collaborations, and I think that’s more important. Obviously, I’m a big fan of his. My favorite movie will always be Bruno, and my favorite line will always be when he looks up at the sky and goes, “So many stars in the sky. Makes you think of all the hot guys in the world.” So freaking random and funny.

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photography by art streiber; Styling by Jill Lincoln and Jordan Johnson for Rachel Zoe Studio at The Wall Group; Makeup by Molly R. Stern at The Wall Group for Rimmel London; Hair by Marcus Francis at The Wall Group; Manicure by Ashlie Johnson at The Wall Group using Chanel Le Vernis